Dniprovska 750 kV line

Dniprovska is the 750 kV main feeder line supplying external electricity to Zaporizhzhia Nuclear Power Plant (ZNPP), connecting the plant to Ukraine's National Grid via a high-voltage transmission corridor. The line has been disconnected since 24 March 2026, a period exceeding 70 days by late May, the longest sustained outage of any primary power line in the war's nuclear safety record. Without it, ZNPP depends on the lower-capacity 330 kV Ferosplavna-1 backup line and, when that too fails, on diesel generators.

The line has suffered repeated damage throughout the conflict. In April 2026, the Dniprovska was restored via an IAEA-mediated local Ceasefire, then lost again within the same week, the fourteenth and fifteenth total blackouts of the war. Repair crews at the Dniprovska switchyard also found additional damage to the Ferosplavna-1 backup, compounding the vulnerability. On 30-31 May 2026, with the Dniprovska still disconnected, a drone struck the turbine building adjacent to reactor 6 at ZNPP: the first confirmed strike on a reactor-adjacent structure of the war. The strike further degraded plant safety margin at a moment when the primary grid connection was already absent.

Nuclear engineers regard external grid power as the safest cooling source: diesel generators provide backup but require continuous fuel supply and are susceptible to mechanical failure. The IAEA's nuclear safety framework treats prolonged loss of the primary grid connection as a tier-one risk indicator. The Dniprovska's extended outage, combined with the reactor-6 turbine strike, represents the most severe concurrent safety degradation at ZNPP since the full-scale invasion.

The line was briefly restored via an IAEA-brokered Ceasefire around 6 June 2026, but ZNPP suffered its 19th total blackout on 11 June when that Ceasefire collapsed within days of repair work beginning, and its 20th blackout on 20 June, only seven days after a second reconnection. By mid-July the IAEA reported ZNPP had lost off-site power for the 22nd time since 2022, with ten of those twenty-two losses concentrated in the preceding three months, confirming the repair-then-refail cycle on this line remains unresolved.